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Anyone up for some IIcx troubleshooting assistance? We have clocks but no activity...
- Thread starter Sideburn
- Start date
Im powering up that ATX supply and the Green LED turns on then i hit reset. I am bypassing the power on circuit. but i fixed that and that works when i connect the real power supply.
BTW there is no oscillation on Y4, the RTC. I ordered some new crystals and they just got here but they are tiny and imm not sure if they are even the right kind because the description calls them both a resonator and an oscillator.
This is what I ordered: https://www.amazon.com/dp/B07Z2W7QM3?psc=1&ref=ppx_yo2ov_dt_b_product_details
And I am about try it. Is this the right kind?
photo attached to see how much smaller it is:
Attachments
Euro timezone.
Need to sleep sorry. But I suggest verifying the address and data lines are good between the cpu and ROMs, via whatever route they take.
I mean, it could try to boot to the flashing question mark this very moment (it wont because of the ram / video / rtc situation)... how would you actually know?
Need to sleep sorry. But I suggest verifying the address and data lines are good between the cpu and ROMs, via whatever route they take.
No, I mean how are you monitoring if you make progress - you have no video, no sound and no serial? What success metric are you using?
I mean, it could try to boot to the flashing question mark this very moment (it wont because of the ram / video / rtc situation)... how would you actually know?
I am looking for square waves on the address and data lines
Exactly... and theres nothing.. The only thing ive got on the entire board are clocks (sign waves, not square waves) and oscillator frequencies.. not one square wave to be found...
No the address lines are stuck low and hen i hit reset the go high and back to low instantly
Ah, I had taken your "address lines go high and low" comment to mean they were doing something. Then your CPU is doing nothing at all, not running, and this shows as it wasn't warm. The fact that it doesn't have /HALT asserted also confuses me. 4.75V is low but not out of spec. What else...
Oops sorry. yeah we are dead..
I know, i just wanted to fix SOMETHING today lol... I put the new one in and ive got my 32khz RTC clock so thats fixed.
*carefully removed with appropriate tooling.
unfortunately it is not socketed.. soldered on the board. nothing on the board is socketed
I seemed to recall those being socketed. Nevermind then. Okay, You have clock, but you have no address lines. CPU resets, but doesn't assert /HALT, nor executes anything. What gives? It feels like a dead CPU, it feels like /HALT is being forced high by a short, it feels like a multitude of things but none seems likely.
I was also afraid it might be a dead cpu
Im not sure which ones those are.. I dont know anything about the 030 pretty much
/IPL2:0, and /IPEND
IPL is Interrupt Priority Level, a 3 bit binary code that tells the CPU to service an interrupt at that level, and IPEND is the processor's acknowledgement an interrupt request was received and its servicing is pending.
All stuck high. How do we know its not bad ROMS or somehting else... should there be a square wave probing on the cpu somewhere no matter what?
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